Centering guide pin for diestocks



Jan. 13, 1942. COME 2,269,756

4 CENTERING GUIDE PIN F OR DIESTOCKS Filed Sept. 25, 1940 N VE'NTDR E153 11; B- EUWI r:.

A-r'ru R L s Patented Jan. 13, 1942 stares CENTERING GUHDE PIN FOR DEESTOCKS James Campbell Cowie, Liverpool, Nova Scotia,

My invention relates to improvements in centering guide pins for die stocks and the object of the invention is to divise a pin which may be adjusted to engage the internal surface of a pipe or nipple end the internal diameter of which has changed through wear or depreciation due to age and it consists essentially of the arrangement and construction of parts as hereinafter described.

Fig. 1 is a sectional view through a die stock and pipe shown in section and my centering pin applied thereto and shown in full.

Fig. 2 is a cross sectional view on line 22 Fig. 1.

Fig. 3 is a cross sectional view on line 3-3 Fig. 1.

Fig. 4 is an enlarged view of the expandible end of the centering pin showing parts in section.

Fig. 5 is a-perspective detail of one of the bars engaging the internal surface of the pipe or nipple Wall.

In the drawing like characters of reference indicate corresponding parts in each figure,

I is a die stock of any common construction reversely set, that is with the threading dies 2 on that side of the stock which is adjacent to the end of the pipe 3 to be threaded. 4 is the main cylindrical body of the centering pin guideably held in the orifice 5 of the bushing 6 forming part of the stock. The body 4 corresponds in diameter to the external diameter of the pipe to be threaded.

The outer end of the body 4 is provided with a knurled head 1 and the inner end with a reduced cylindrical portion a corresponding in diameter to the internal diameter of the pipe to be threaded. Extending centrally from the inner end of the portion 8 is a further reduced portion 9 in which are formed the threaded sections In and H.

I2 are gripping bars each having inclined internal cam faces l3 and I4 opposite the threaded sections [0 and I l and a central transverse groove through which the split securing ring I6 extends to resiliently bind the bars I2 together.

I1 and I8 are nuts engaging the threaded sections I0 and H and provided with radial jaws l9 having inclined bottom faces 20 corresponding to and engaging the faces I3 and [4.

Before the eXpa-ndible end of the centering pin is inserted in the pipe 3 and in the die stock the head 'IV is manually turned, the other hand holding the bars l2 and nuts I1 and l8 from rotation. By this means the nuts I! and I8 are screwed to move longitudinally in a leftwise direction, the contacting inclined surfaces l3 and M of the bars and 2t of the nuts forcing the bars outward against the tension of the split ring I6 to the internal diameter of the pipe 3 into which the adjuster pin is slipped to form a guide for the dies and stock as the external thread is cut in the pipe 3.

In cases where the pipe to be threaded depends vertically I support the centering pin by an annular disc 21 secured around the cylindrical body 4 by a pin 22 so as to rest on the bushing 6.

The centering pin can also be used as a nipple holder for threading nipples. The nipple holder need not be reversible and it can also be used on power pipe machines as a nipple holder.

What I claim as my invention is:

An independent centering pin adaptable for use in any standard die stock and comprising a closure for the side of the stock remote from the dies and having an orifice in axial alignment with a point centered between the cutting ends of the dies, a centering pin body fitting the orifice having a knurled enlargement at its outer end and a reduced extension at its inner end forming an intermediate pin portion, a further extension having an exterior thread, a pair of spaced apart nuts screwed on the thread and having diametrically opposite notches formed therein in longitudinal alignment, and having parallelly inclined bottoms, gripping bars fitting the notches and having inclined surfaces engaging each inclined surface of the nuts and of greater length than the width of the nuts, and yieldable means for holding the inclined surfaces of the nuts and bars in engagement.

JAMES CAMPBELL COWIE. 

